Results. Of 559 patients who received the open-label first course of rituximab, 475 patients were randomized to a second course (rituximab retreatment: n = 318, placebo retreatment: n = 157). Relative to baseline, patients who took rituximab during retreatment had significantly improved efficacy at Week 48 compared to patients who took a placebo during retreatment [American College of Rheumatology (ACR20) criteria, 54% vs 45%, p = 0.02; change in Disease Activity Score-28 mean −1.9 vs −1.5, p = 0.006]. Differences in efficacy between groups were first observed following Weeks 28–32. Worsening of most components of the ACR core set occurred in the placebo-retreated patients with relative maintenance of these measures in rituximab-retreated patients. Randomized patients who had achieved week 24 ACR responses following the first course had greater odds of losing response if retreated with placebo (odds ratios for ACR20, ACR50, ACR70: 2.09, 2.03, and 4.09, respectively). Following retreatment, the proportion of patients experiencing any adverse events (AE), serious AE, infections, and serious infections were comparable between the rituximab and placebo retreatment groups.

Conclusion. Two courses of rituximab about 6 months apart resulted in improved and sustained efficacy at 1 year, compared with 1 course, with a similar safety profile.